1. Field of the Invention
The present invention relates to a radio communication system, a radio base station, and a mobile station control method controlling a mobile station using a transmission power ratio between an uplink physical data channel and an uplink physical control channel.
2. Description of the Related Art
The third generation partnership project (3GPP) has been studying and creating a specification of the third generation mobile phone system based on a code division multiple access (CDMA) scheme, and has defined an enhanced uplink (EUL) in which an uplink communication rate is increased (e.g. “3GPP TS 25.309 V.6.6.0 FDD Enhanced Uplink Overall description Stage 2 (Release 6),” 3GPP, March, 2006).
EUL uses a physical channel such as a physical data channel, i.e., an enhanced dedicated physical data channel (E-DPDCH), and a physical control channel, i.e., an enhanced dedicated physical control channel (E-DPCCH). Further, in EUL, a radio base station informs a mobile station of a maximum allowable transmission power ratio between an E-DPDCH and an E-DPCCH, as a scheduling grant (SG).
When determining a SG, the radio base station needs to recognize βed being a transmission power offset per transport format combination indicator (E-TFCI) in a mobile station. A radio network controller (RNC) informs the radio base station of parameters necessary for the calculation of βed (e.g. Reference E-TFCI, and Reference E-TFCI Power Offset) through a Node B Application Part (NBAP) message. In addition, the RNC notifies the mobile station of the parameters through a radio resource control (RRC) message.
However, a method of determining the above-described scheduling grant (SG) has the following problem. That is, when determining the SG, the radio base station must calculate a βed for each E-TFCI for each call generated between itself and the mobile station on the basis of the parameters informed by the RNC. Further, the radio base station must create a correspondence table for the SG and E-TFCI. Alternatively, the radio base station must calculate the SG on the basis of a receivable transport block (TB) size as a resource of the radio base station for each scheduling.
Therefore, the radio base station has a problem that processing load is increased due to the calculation needed to determine the SG.
In light of this problem, the present invention has been made, and an object thereof is to provide a radio communication system, a radio base station, and a mobile station control method that are capable of reducing processing load on a determination of the scheduling grant (SG) being a maximum allowable transmission power ratio between the physical data channel (E-DPDCH) and the physical control channel (E-DPCCH) defined for the mobile station, while using existing messages between a radio network controller and a radio base station, and between the radio network controller and the mobile station.